JP3958538B2 - Concrete hammering inspection method and concrete hammering inspection apparatus - Google Patents

Description

【００４３】
上式（１）において、積分項の関数ψの部分は、関数ψ（ｘ）の複素共役関数を示している。また、逆に、上式（１）から、元の波形信号ｆ（ｘ）を復元することができる。この場合には、上記したウェーヴレット変換の逆変換、すなわち逆ウェーヴレット変換（Ｉｎｖｅｒｓｅ Ｗａｖｅｌｅｔ Ｔｒａｎｓｆｏｒｍ）を行うことになる。逆ウェーヴレット変換は、下式（２）によって定義される。
【００４４】
【数２】

【００４５】
ウェーヴレット変換を行った後に、各次数（各周波数）ごとに逆ウェーヴレット変換を行えば、図４に示すように、時間ｘを横軸とし周波数ｙを縦軸とする平面上で、打音の強さｚを表す関数ｆ（ｘ）を、各周波数ごとに分解して復元することができる。例えば、図４において、周波数ｆ１における関数成分として関数ｇ１（ｘ）を、また周波数ｆ２における関数成分として関数ｇ２（ｘ）を、また周波数ｆ３における関数成分として関数ｇ３（ｘ）を、また周波数ｆ４における関数成分として関数ｇ４（ｘ）を、それぞれ得ることができる。
【００４６】
本実施形態の解析部３においては、上述したように、マザー・ウェーヴレットとして、Ｂａｔｔｌｅ−Ｌｅｍａｒｉｅのマザー・ウェーヴレットを採用しているが、これにより、各周波数ｆ１等での関数ｇ１（ｘ）等の波形は、最初は振幅値が増加していき、振幅値がピークに到達した後は、時間の経過とともに振幅値が概ね減衰していく正弦波形（減衰調和振動）、例えば、音の強さをｚとすると、下式（３）
ｚ＝Ａ・ｅｘｐ（−ｋｘ）・ｓｉｎ（ωｘ＋δ） ………（３）
に近い関数となる。ここに、ｅｘｐは、自然指数関数を表しており、Ａ、ｋ、ωは、ともに正の実数を表している。δは、実数である。
【００４７】
本実施形態の解析部３においては、コンクリート部材を打撃した場合に個人差が生じる場合（採取したマイクロフォンの音の強さに差がある場合）をも想定し、これを正規化して誤差を防止する処理課程を設けている。すなわち、逆ウェーヴレット変換後の各周波数における波形において振幅値が最大となるときの振幅値を所定値（本実施形態の場合は１００）とし、全体が相似な波形となるように処理している。
【００４８】
次に、本実施形態の解析部３は、逆ウェーヴレット変換後の各周波数における波形において、「実効値」と呼ばれる値を演算する。この実効値は、逆ウェーヴレット変換後の各周波数における波形において、波形振幅最大値Ａ１，Ａ２，…をすべて算出し、互いに連続（隣接）する３個の値、例えば、Ａ１とＡ２とＡ３、の平均値（Ａ１＋Ａ２＋Ａ３）／３を算出して、これらの各平均値を、３個の組の最初の振幅最大値の位置、例えば、Ａ１とＡ２とＡ３の組の場合はＡ１の位置、にプロットするのである。次に、このようにして得られた離散値の間を「３次スプライン補間」と呼ばれる手法により補間して滑らかな曲線とする。３次スプライン補間は、隣り合う点を、２次導関数によって連続的に結ぶ補間方法である。
【００４９】
上記のような処理により、逆ウェーヴレット変換後の各周波数の横線（以下、「周波数線」という。）の上には、多少の凹凸はあるものの、最初は増加し、ピークに到達した後は、時間ｘの経過とともに概ね減衰するような曲線が描かれる。以下、この曲線を「打音実効曲線」という。これらの打音実効曲線をもとに、縦軸方向（周波数方向）についても、上記のような３次スプライン補間等の補間を施すことにより、滑らかな曲面を得ることができる。この曲面は、打音の継続時間をｘ軸とし、打音の周波数をｙ軸とし、打音の強さをｚ軸とする３次元直交座標空間（以下、「打音解析空間」という。）の中に描かれるものであり、以下、「打音曲面」という。
【００５０】
図５は、図１に示すコンクリート打音検査装置１００の画像表示部４に表示される打音解析空間における打音曲面を示す概念図である。また、打音曲面は、ｘｙ平面（打音継続時間ｘ軸と打音周波数ｙ軸によって決定される平面。以下、「打音継続時間・周波数平面」という。）の上に、音の強さｚの値の等しい箇所を等高線で結んで表示してもよい。図６は、そのようにｘｙ平面にｚ値を等高線表示した図のうち、コンクリート部材の劣化を評価する場合の特徴的形状を説明する概念図である。
【００５１】
出願人らは、コンクリート部材（図示せず）の表面を打撃した際に発生する打音を、上記したコンデンサマイクロフォン１で検出し、信号処理部２で信号処理した後、解析部３で上記の時間・周波数分析を行い、打音曲面を画像表示部４に表示させる室内実験及び現場試験を多数行った結果、ｘｙ平面にｚ値を等高線表示するようにして打音曲面を表示した場合の形状と、コンクリート部材の劣化状態との間に一定の関連性があることを発見した。
【００５２】
すなわち、図６に示すように、コンクリート部材に劣化部分が存在する場合には、その劣化の種類や程度に応じて、打音曲面には、「Ａゾーン」、「Ｂゾーン」、「Ｃゾーン」として示される特徴的な領域が現れる。以下、これらについて説明を行う。
【００５３】
図６に示すＡゾーンは、ｘｙ平面のうち、打音の継続時間ｘが短く、かつ周波数ｙが高い領域、すなわち、ｘｙ平面の縦軸（周波数軸）付近の上方、換言すれば、ｘｙ平面の左上部付近に現れる。実験の結果、コンクリート部材の強度が高い場合には、Ａゾーンは、ｙ軸付近で、かつｘｙ平面のかなり上方に現れた。一方、コンクリート部材の強度が低い場合には、Ａゾーンは、ｙ軸付近だが、ｙ方向の位置は低くなる。そして、コンクリート部材の強度が非常に低くなると、Ａゾーンのｙ方向の高さ位置は、さらに低い位置となることが、実験によって明らかになった。このことから、このＡゾーンの位置の周波数（ｙ値）は、コンクリート部材の持っている強度の程度を示している、と考えられる。実験結果によれば、コンクリート部材の圧縮強度が約２０ＭＰａ（メガパスカル）の場合、Ａゾーンの周波数ｙは約１．４〜１１．０ｋＨｚ程度であった。また、打音の継続時間ｘについて見ると、例えば、周波数が２．８ｋＨｚのとき、打音データの取り込み開始時点から約１ｍｓｅｃで最大値に到達し、その後１ｍｓｅｃでピークは終了した。したがって、Ａゾーンの時間範囲は、ｘ＝０の時点（打音データ取り込み時点）から約２ｍｓｅｃ程度を考慮すればよいと考えられる。
【００５４】
次に、図６に示すＢゾーンは、ｘｙ平面のうち、打音の継続時間ｘがやや短く、かつ周波数ｙがほぼ中間の領域、すなわち、ｘｙ平面の縦軸（周波数軸）にやや近い中間の部分、換言すれば、ｘｙ平面の左半分の中央付近に現れる。実験の結果、コンクリート部材の内部のある箇所において、主として粗骨材が取り残され、細骨材やセメント分が他へ流出して空隙となったような状態となった部分、いわゆる「ジャンカ」と呼ばれる部分が存在する場合には、Ａゾーンの下方にＢゾーンが現れることが多かった。このＢゾーンの音は、実際に聴取すると、「グシャッ」というように聞こえる。このことから、このＢゾーンが現れた場合は、コンクリート部材の内部に、ジャンカ、コールドジョイントのような何らかの欠陥が存在していることを示している、と考えられる。実験結果によれば、コンクリート部材の圧縮強度が約２０ＭＰａで内部にジャンカが存在する場合、Ｂゾーンの周波数ｙは約３４５Ｈｚ〜１．４ｋＨｚ程度であり、打音の継続時間ｘは１５ｍｓｅｃ程度であった。
【００５５】
次に、図６に示すＣゾーンは、ｘｙ平面のうち、打音の継続時間ｘはほぼ全域に及んでおり、かつ周波数ｙが低い領域、すなわち、ｘｙ平面の横軸（打音継続時間軸）に沿った下方の部分、換言すれば、ｘｙ平面の下半分に現れる。実験の結果、コンクリート部材の支持条件、例えば、コンクリート部材の下部が支持されている場合、下面全体が支持されているのではなく、コンクリート部材の一部のみが支持されている場合、例えば、コンクリート部材の両端が単純支持されているような場合には、横方向（ｘ軸方向）に長く延びる顕著なＣゾーンが現れることが多かった。また、コンクリート部材の支持条件が良好となり、例えばコンクリート部材の下部の部分の支持箇所が増えると、Ｃゾーンのｘ軸方向の長さは短くなることがわかった。このことから、このＣゾーンは、コンクリート部材の背後の支持状態の程度を示している、と考えられる。実験結果によれば、コンクリート部材の圧縮強度が約２０ＭＰａで単純支持条件の場合、Ｃゾーンは周波数約８６Ｈｚ程度を中心とする領域であり、打音の継続時間ｘは５０ｍｓｅｃ程度まで残っていた。
【００５６】
上記のことを踏まえ、このコンクリート打音検査装置１００の解析部３では、上記したＡ、Ｂ、Ｃゾーンの存在を検出し、その程度を判別し評価することとしている。以下、その内容について、詳細に説明する。
【００５７】
まず、Ａゾーンの検出とその評価について説明する。上記したＡゾーンの性質から、解析部３の解析においては、「Ａゾーンは、打音開始時（ｘ＝０の時点）から２ｍｓｅｃの時間範囲内に現れる。」と設定した。そして、下記のような計算や処理を行った。
【００５８】
最初に、各周波数の横線である周波数線（ｘ軸に平行な線）上の打音実効曲線のそれぞれについて、打音開始時（ｘ＝０）からｘ＝２ｍｓｅｃまでの積分値（ｘが０と２ｍｓｅｃの間の打音実効曲線とｘｙ平面との間の略台形状の部分の面積）を算出する。これにより、例えば、周波数ｆ１の場合の面積がｓ１、周波数ｆ２の場合の面積がｓ２、周波数ｆ３の場合の面積がｓ３、…、周波数ｆｉの場合の面積がｓｉ、…、周波数ｆｎ−１の場合の面積がｓｎ−１、周波数ｆｎの場合の面積がｓｎ、というような値が求められる。
【００５９】
次に、これらの面積の総和ｖ１＝Σｓｉを求める。次に、各周波数の面積ｓｉに、その周波数ｆｉを乗じて得た積（ｓｉ×ｆｉ）の総和ｖ２＝Σ（ｓｉ×ｆｉ）を求める。そして、値ｖ２を値ｖ１で除した商ｖ３＝（ｖ２／ｖ１）を算出する。この値ｖ３は、仮想の周波数を表しており、これは、図７（Ａ）のＡゾーンの重心に相当する周波数ｙ_ga（以下、「Ａゾーン重心周波数」という。）に等しいと考えられる。また、打音開始から２ｍｓｅｃの時間は、図７（Ａ）における第１打音継続時間ｘ１に相当している。また、打音開始から２ｍｓｅｃまでの時間領域は、特許請求の範囲における第１領域に相当している。
【００６０】
したがって、Ａゾーンの性質より、Ａゾーン重心周波数ｙ_gaが、ある周波数値ｙ_tよりも低い場合には、そのコンクリート部材の打撃点付近の強度は、所定値よりも低いと考えられる。この場合の所定値がコンクリートの設計強度と等しくなるようにある周波数値ｙ_tを設定すれば、コンクリート部材の打撃点付近は「強度が劣化している」と判断することができる。以下、このときのｙ_tを「判別周波数」という。判別周波数ｙ_tは、例えば、１０００〜４０００Ｈｚ（１〜４ｋＨｚ）といった範囲の値となると考えられる。
【００６１】
本実施形態のコンクリート打音検査装置１００の解析部３では、図８（Ａ）に示すような評価画面の画像データを作成し、画像表示部４に出力して表示させるようにしている。すなわち、「Ａゾーン評価」として、赤色のバーＣ１と、黄色のバーＣ２と、緑色のバーＣ３がそれぞれ隣接して表示される。ここに、赤色バーＣ１は、危険な（劣化した）範囲を表現している。また、黄色バーＣ２は、注意（警戒）すべき範囲を表現している。また、緑色バーＣ３は、良好な（劣化のおそれの無い）範囲を表現している。
【００６２】
ここで、赤色のバーＣ１と黄色のバーＣ２の境界の値は、例えば３０００（Ｈｚ）に設定されている。また、黄色のバーＣ２と緑色のバーＣ３の境界の値は、例えば６０００（Ｈｚ）に設定されている。これらのうち、値が３０００の境界線は、劣化の判別基準となる判別周波数を表している。そして、上記のようにして演算された値ｖ３（又はＡゾーン重心周波数ｙ_ga）の値が、スコア欄Ｗ１に、例えば「５２４６」などと表示される。また、このスコア欄Ｗ１の数値に相当する位置に、黒色の評価線Ｌ１が表示される。評価線Ｌ１は、目立つように、点滅表示させてもよい。図８（Ａ）の場合は、評価線Ｌ１が黄色バーＣ２の範囲にあることを示している。このような画像表示により、このコンクリート打音検査装置１００の使用者は、コンクリート部材の強度の劣化程度を数値的又は感覚的に判断することができる。
【００６３】
次に、Ｂゾーンの検出とその評価について説明する。Ｂゾーンの評価にあたっては、下記のような計算や処理を行った。
【００６４】
各周波数における横線である周波数線（ｘ軸に平行な線）の上における打音実効曲線について、その最大値を検出する。例えば、周波数ｆ１の場合の打音実効曲線の最大値をｈ１とする。次に、打音実効曲線の上で、その値が、ｈ１に対して所定の比率（本実施形態の場合は５％）となる値まで減衰したときのｈ１からの経過時間を「有効減衰時間」と定義し、ｔ_d1で表すことにする。また、同様にして、周波数ｆ２の場合の有効減衰時間ｔ_d2を求め、以下、同様に、ｉ番目の周波数ｆｉにおける有効減衰時間ｔ_diを求め、最後の（ｎ番目の）周波数ｆｎにおける有効減衰時間ｔ_dnまで求める。
【００６５】
次に、これらの有効減衰時間の加重平均値ｖ４＝（Σｔ_di）／ｎを求める。この値は、仮想の時間を表しており、これは、図７（Ｂ）のＢゾーンの重心に相当する時間ｘ_gb（以下、「Ｂゾーン重心時間」という。）に等しいと考えられる。なお、Ｂゾーンは、第１周波数ｙ１以下の領域（第２領域）に現れるはずであるが、周波数の高い領域での有効減衰時間ｔ_diの値は非常に小さいと考えられるため、周波数の高い領域の成分は、Ｂゾーン重心時間ｘ_gbにはほとんど寄与しないと考えられ、結果的に、有効減衰時間の加重平均値ｖ４は、第１周波数ｙ１以下の領域を対象とすることとなる、と考えられる。
【００６６】
したがって、Ｂゾーンの性質より、Ｂゾーン重心時間ｘ_gbが、ある時間値ｘ_t1よりも大きい場合には、そのコンクリート部材の打撃点付近の内部に欠陥が存在すると考えられる。この場合の所定値が、内部にジャンカが存在する場合、あるいは内部にコールドジョイントが存在する場合と等しくなるようにある時間値ｘ_t1を設定すれば、コンクリート部材の打撃点付近に「内部欠陥が存在する」と判断することができる。以下、このときのｘ_t1を「第１判別時間」という。第１判別時間ｘ_t1は、例えば、１０〜１５ｍｓｅｃといった範囲の値となると考えられる。
【００６７】
本実施形態のコンクリート打音検査装置１００の解析部３では、図８（Ｂ）に示すような評価画面の画像データを作成し、画像表示部４に出力して表示させるようにしている。すなわち、「Ｂゾーン評価」として、緑色のバーＣ４と、黄色のバーＣ５と、赤色のバーＣ６がそれぞれ隣接して表示される。ここに、赤色バーＣ６は、危険な（内部欠陥のある）範囲を表現している。また、黄色バーＣ５は、注意（警戒）すべき範囲を表現している。また、緑色バーＣ４は、良好な（内部欠陥のおそれの無い）範囲を表現している。
【００６８】
ここで、赤色のバーＣ６と黄色のバーＣ５の境界の値は、例えば８（ｍｓｅｃ）に設定されている。また、黄色のバーＣ５と緑色のバーＣ４の境界の値は、例えば３（ｍｓｅｃ）に設定されている。これらのうち、値が８の境界線は、内部欠陥の判別基準となる第１判別時間を表している。そして、上記のようにして演算された値ｖ４（又はＢゾーン重心時間ｘ_gb）の値が、スコア欄Ｗ２に、例えば「２．５」などと表示される。また、このスコア欄Ｗ２の数値に相当する位置に、黒色の評価線Ｌ２が表示される。評価線Ｌ２は、目立つように、点滅表示させてもよい。図８（Ｂ）の場合は、評価線Ｌ２が緑色バーＣ４の範囲にあることを示している。このような画像表示により、このコンクリート打音検査装置１００の使用者は、コンクリート部材の内部欠陥の程度を数値的又は感覚的に判断することができる。
【００６９】
次に、Ｃゾーンの検出とその評価について説明する。Ｃゾーンの評価にあたっては、下記のような計算や処理を行った。
【００７０】
各周波数における横線である周波数線（ｘ軸に平行な線）の上における打音実効曲線について、その最大値を検出する。例えば、周波数ｆ１の場合の打音実効曲線の最大値をｈ１とする。次に、打音実効曲線の上で、その値が、ｈ１に対して所定の比率（本実施形態の場合は５％）となる値まで減衰したときのｈ１からの経過時間を「有効減衰時間」と定義し、ｔ_d1で表すことにする。また、同様にして、周波数ｆ２の場合の有効減衰時間ｔ_d2を求め、以下、同様に、ｉ番目の周波数ｆｉにおける有効減衰時間ｔ_diを求め、最後の（ｎ番目の）周波数ｆｎにおける有効減衰時間ｔ_dnまで求める。
【００７１】
次に、これらの有効減衰時間のうち、最大のものｔ_dmaxを検出する。この値は、仮想の時間を表しており、これは、図７（Ｃ）のＣゾーンの上端（右端）に相当する時間ｘ_ec（以下、「Ｃゾーン上端時間」という。）に等しいと考えられる。なお、Ｃゾーンは、第２周波数ｙ２以下の領域（第３領域）に現れるはずであるが、周波数の高い領域での有効減衰時間ｔ_diの値は非常に小さいと考えられるため、周波数の高い領域の成分は、Ｃゾーン上端時間ｘ_ecにはほとんど寄与しないと考えられ、結果的に、第２周波数ｙ２以下の領域を対象とすることとなる、と考えられる。
【００７２】
したがって、Ｃゾーンの性質より、Ｃゾーン上端時間ｘ_ecが、ある時間値ｘ_t2よりも大きい場合には、そのコンクリート部材の打撃点付近に背後の支持状態が不良な箇所が存在すると考えられる。この場合の所定値が、内部に空洞部が存在する場合などと等しくなるようにある時間値ｘ_t2を設定すれば、コンクリート部材の打撃点付近の「支持状態が不良である」と判断することができる。以下、このときのｘ_t2を「第２判別時間」という。第２判別時間ｘ_t2は、例えば、１５〜５０ｍｓｅｃといった範囲の値となると考えられる。
【００７３】
本実施形態のコンクリート打音検査装置１００の解析部３では、図８（Ｃ）に示すような評価画面の画像データを作成し、画像表示部４に出力して表示させるようにしている。すなわち、「Ｃゾーン評価」として、緑色のバーＣ７と、黄色のバーＣ８と、赤色のバーＣ９がそれぞれ隣接して表示される。ここに、赤色バーＣ９は、危険な（支持状態の不良な）範囲を表現している。また、黄色バーＣ７は、注意（警戒）すべき範囲を表現している。また、緑色バーＣ６は、良好な（支持不良のおそれの無い）範囲を表現している。
【００７４】
ここで、赤色のバーＣ９と黄色のバーＣ８の境界の値は、例えば２０（ｍｓｅｃ）に設定されている。また、黄色のバーＣ７と緑色のバーＣ６の境界の値は、例えば１０（ｍｓｅｃ）に設定されている。これらのうち、値が２０の境界線は、支持不良の判別基準となる第２判別時間を表している。そして、上記のようにして演算されたＣゾーン上端時間ｘ_ecの値が、スコア欄Ｗ３に、例えば「２３．１」などと表示される。また、このスコア欄Ｗ３の数値に相当する位置に、黒色の評価線Ｌ３が表示される。評価線Ｌ３は、目立つように、点滅表示させてもよい。図８（Ｃ）の場合は、評価線Ｌ３が赤色バーＣ９の範囲にあることを示している。このような画像表示により、このコンクリート打音検査装置１００の使用者は、コンクリート部材の支持不良の程度を数値的又は感覚的に判断することができる。
【００７５】
次に、打音検査の総合評価について説明する。総合評価にあたっては、下記のような計算や処理を行った。
【００７６】
まず、各周波数における横線である周波数線（ｘ軸に平行な線）の上における打音実効曲線について、スプライン補間を行う前の離散値を読み出す。次に、打音開始時点（ｘ＝０）から４０ｍｓｅｃの期間の全部の離散値を、ある周波数について総和する。次に、この総和を、すべての（ｎ個の）周波数について、総和する。この総和値をＳ_f,40とする。次に、スプライン補間前の各離散値を、この総和値Ｓ_f,40で除することにより正規化を行う。
【００７７】
次に、時間軸（ｘ軸）方向に、打音開始時点（ｘ＝０）では、値が「＋１」となり、打音開始時点（ｘ＝０）から４０ｍｓｅｃ後の時点では、値が「−１」となるような１次直線（以下、「時間方向重み係数直線」という。）を求める。すなわち、時間方向の重み付け係数は、時間値が大きくなるほど小さくなり、最後は負の値となる。
【００７８】
各周波数における横線である周波数線（ｘ軸に平行な線）の上において、離散値に、その値に対応する位置の時間方向重み係数直線の値を乗じて、「重み付け離散値」を求める。そして、各周波数における周波数線ごとに、重み付け離散値の総和を計算する。すなわち、周波数が小さい順に、周波数ｆ１の場合の重み付け離散値の総和である時間方向和をσ１とし、周波数ｆ２の場合の重み付け離散値の総和である時間方向和をσ２とし、…、以下同様にして周波数ｆｉの場合の重み付け離散値の総和である時間方向和をσｉとし、…、周波数ｆｎ−１の場合の重み付け離散値の総和である時間方向和をσｎ−１とし、周波数ｆｎの場合の重み付け離散値の総和である時間方向和をσｎとする。
【００７９】
次に、周波数が最も高い周波数ｆｎの場合の周波数方向重み付け係数ｋｎを１とし、次に高い周波数ｆｎ−１の場合の周波数方向重み付け係数ｋｎ−１を１／２とし、次に高い周波数ｆｎ−２の場合の周波数方向重み付け係数ｋｎ−２を１／４とし、…、周波数ｆｉの場合の周波数方向重み付け係数ｋｉを１／（２^n-i）とし、…、周波数ｆ３の場合の周波数方向重み付け係数ｋ３を１／（２^n-3）とし、周波数ｆ２の場合の周波数方向重み付け係数ｋ２を１／（２^n-2）とし、最も低い周波数ｆ１の場合の周波数方向重み付け係数ｋ１を１／（２^n-1）とする。すなわち、周波数方向の重み付け係数ｋｉは、周波数が高くなるほど正の値で大きくなる。
【００８０】
次に、上記した周波数ｆｉの場合の時間方向和σｉに、周波数方向の重み付け係数ｋｉを乗じ、すべての（ｎ個の）周波数について、これらの積の総和を求め、これを総合評価値とする。そして、総合評価値が大きいほど、コンクリート部材は良好な状態であると評価する。すなわち、総合評価においては、打音継続時間が長いものほど評価が小さくなるように重み付けを大きくし、かつ、周波数が高いものほど評価が大きくなるように重み付けを大きくしている。
【００８１】
本実施形態のコンクリート打音検査装置１００の解析部３では、図８（Ｄ）に示すような評価画面の画像データを作成し、画像表示部４に出力して表示させるようにしている。すなわち、「総合評価」として、赤色のバーＣ１０と、黄色のバーＣ１１と、緑色のバーＣ１２がそれぞれ隣接して表示される。ここに、赤色バーＣ１０は、危険な（コンクリート部材の品質に問題がある）範囲を表現している。また、黄色バーＣ１１は、注意（警戒）すべき範囲を表現している。また、緑色バーＣ１２は、良好な（コンクリート部材の品質に問題の無い）範囲を表現している。
【００８２】
ここで、赤色のバーＣ１０と黄色のバーＣ１１の境界の値、あるいは、黄色のバーＣ１１と緑色のバーＣ１２の境界の値は、適宜の値に設定されている。例えば、赤色のバーＣ１０と黄色のバーＣ１１の境界の値は、負の値となる場合もある。そして、上記のようにして演算された総合評価値が、スコア欄Ｗ４に、例えば「３２」などと表示される。また、このスコア欄Ｗ４の数値に相当する位置に、黒色の評価線Ｌ４が表示される。評価線Ｌ４は、目立つように、点滅表示させてもよい。図８（Ｄ）の場合は、評価線Ｌ４が緑色バーＣ１２の範囲にあることを示している。このような画像表示により、このコンクリート打音検査装置１００の使用者は、コンクリート部材の総合評価の程度を数値的又は感覚的に判断することができる。
【００８３】
上記のように構成することにより、本実施形態のコンクリート打音検査装置１００は、以下のような利点を有している。
【００８４】
一定の条件でコンクリート部材を打撃し、その際に発生する打音を所定の論理で処理し、評価値を算出して強度劣化等の評価を行うため、検査者には特に経験等は不要であり、診断結果に検査担当者の個人差（結果のバラツキ）が生じることがなく、診断結果として定量的な評価を容易に下すことができる、といった利点がある。
【００８５】
上記の実施形態において、解析部３の図示しないＣＰＵは、特許請求の範囲における時間・周波数分析手段、及び評価手段に相当している。
【００８６】
なお、本発明は、上記各実施形態に限定されるものではない。上記実施形態は、例示であり、本発明の特許請求の範囲に記載された技術的思想と実質的に同一な構成を有し、同様な作用効果を奏するものは、いかなるものであっても本発明の技術的範囲に包含される。
【００８７】
例えば、上記実施形態においては、音響検出手段としてコンデンサマイクロフォンを例に挙げて説明したが、本発明はこれには限定されず、他の構成の音響検出手段、例えば、エレクトレットマイクロフォン等であってもよい。
【００８８】
また、上記実施形態においては、時間・周波数分析の手法としてウェーヴレット逆変換を例に挙げて説明したが、本発明はこれには限定されず、他の時間・周波数分析手法、例えば、短時間フーリエ逆変換（ＳＴＦＴ：Ｓｈｏｒｔ Ｔｉｍｅ Ｆｏｕｒｉｅｒ Ｔｒａｎｓｆｏｒｍ）、ウィグナー分布（ＷＤ：Ｗｉｇｎｅｒ Ｄｉｓｔｒｉｂｕｔｉｏｎ）等を採用してもよい。
【００８９】
【発明の効果】
以上説明したように、本発明によれば、コンクリート部材の打音を音響検出手段により検出し、データをデータ変換手段によりディジタル波形データに変換し、時間・周波数分析手段によって時間・周波数分析することにより、打音継続時間ｘと打音周波数ｙと打音強さｚからなる打音分析データ（ｘ，ｙ，ｚ）を算出し、打音分析データを３次元の打音解析空間にプロットして得られる打音曲面の形状を判別することによりコンクリート部材の劣化の有無及び程度を評価するように構成したので、一定の条件でコンクリート部材を打撃し、その際に発生する打音を所定の論理で処理し、評価値を算出して強度劣化等の評価を行うため、検査者には特に経験等は不要であり、診断結果に検査担当者の個人差（結果のバラツキ）が生じることがなく、診断結果として定量的な評価を容易に下すことができる、といった利点がある。
【図面の簡単な説明】
【図１】本発明の一実施形態であるコンクリート打音検査装置の構成を示すブロック図である。
【図２】図１に示すコンクリート打音検査装置の解析部におけるウェーヴレット逆変換に用いられるウェーヴレットの一例を示す図である。
【図３】打音の波形データとウェーヴレットとの関係を説明する概念図である。
【図４】打音の波形データと逆ウェーヴレット変換との関係を説明する概念図である。
【図５】図１に示すコンクリート打音検査装置の画像表示部に表示される打音解析空間における打音曲面を示す概念図である。
【図６】図１に示すコンクリート打音検査装置の画像表示部に表示される打音曲面を打音継続時間・周波数平面の上に等高線表示した図のうち、コンクリート部材の劣化を評価する場合の特徴的形状を説明する概念図である。
【図７】図１に示すコンクリート打音検査装置におけるＡ〜Ｃゾーンの評価方法を説明する概念図である。
【図８】図１に示すコンクリート打音検査装置の画像表示部に表示される打音検査結果の評価画面の例を示す概念図である。
【符号の説明】
１ コンデンサマイクロフォン
２ 信号処理部
３ 解析部
４ 画像表示部
５ データ・指令入力部
１００ コンクリート打音検査装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for inspecting deterioration of a concrete member by analyzing a sound when the surface of the concrete member is hit.
[0002]
[Prior art]
Recently, deterioration of quality occurring in concrete members of buildings has become a problem in railways and roads. For example, there are cavities on the backside of tunnel lining concrete, places where strength has decreased, or phenomena such as peeling or dropping of concrete pieces due to neutralization of concrete ramen viaducts.
[0003]
These concrete structures constitute the travel route of vehicles for transportation, and it is necessary to detect deterioration and deformation at an early stage and take appropriate measures such as repair from the viewpoint of traveling safety. .
[0004]
As one of the methods for inspecting deterioration of a concrete member as described above, hitting the surface of the concrete member with a hammer or the like and listening to the generated sound (hereinafter referred to as “hitting sound”). An inspection method (hereinafter referred to as a “sound percussion inspection method”) is used.
[0005]
[Problems to be solved by the invention]
However, in the conventional hammering test method described above, the test is performed by a human, and the inspector is required to have sufficient experience, and the diagnosis result depends on the sensitivity of the tester to the hammering sound. (Fluctuation of results) occurred, and qualitative evaluation was possible as a diagnosis result, but quantitative evaluation was difficult.
[0006]
The present invention has been made in order to solve the above problems, and the problem to be solved by the present invention can be easily performed even by a person with little inspection experience, and there is no individual difference and quantitative evaluation is possible. An object of the present invention is to provide a concrete hammering inspection method and a concrete hammering inspection apparatus.
[0007]
[Means for Solving the Problems]
  In order to solve the above-described problems, a concrete hammering test method according to the present invention detects a hammering sound generated when a surface of a concrete member is hit by an acoustic detection means, and detects analog waveform data of the detected hammering sound as data. Sampling is performed at a time interval Δt by the conversion means, and the sound waveform amplitude value is discretized to be converted into digital waveform data, and the converted digital waveform data is analyzed by time / frequency analysis by the time / frequency analysis means. The sound analysis data (x, y, z) including the sound duration x, the frequency y of the sound and the strength z of the sound is calculated, and the sound analysis data (x, y, z) is calculated. By discriminating the shape of the sound-sounding curved surface obtained by plotting in a sound-sounding analysis space, which is a three-dimensional coordinate space composed of mutually orthogonal x-axis, y-axis, and z-axis Evaluating the presence and degree of deterioration of the serial concrete memberIn addition, the hitting sound that is the center of gravity position of the A zone curved surface that is the hitting curved surface in the first region in which the value of the hitting sound duration time x is equal to or shorter than the first hitting sound duration time x1 from the start of the hitting sound to 2 msec. A zone center-of-gravity frequency y which is frequency y _ga Discriminating frequency y selected from 1000 Hz to 4000 Hz _t If lower than that, it is evaluated that there is a strength deterioration portion in the vicinity of the striking point of the concrete member.It is characterized by that.
[0009]
  Also,The concrete hammering sound inspection method according to the present invention detects a hammering sound generated when the surface of a concrete member is hit by the acoustic detection means, and detects analog waveform data of the detected hammering sound at a time interval Δt by the data conversion means. Sampling and digitizing the sound waveform amplitude value to convert it into digital waveform data, and analyzing the converted digital waveform data by time / frequency analysis means by time / frequency analysis means, The sound analysis data (x, y, z) comprising the frequency y of the sound and the strength z of the sound is calculated, and the sound analysis data (x, y, z) is orthogonal to the x axis and y. By discriminating the shape of the percussion surface obtained by plotting in a percussion analysis space, which is a three-dimensional coordinate space consisting of an axis and a z-axis, To evaluate the presence and extent of,The value of the sound hit frequency y is equal to or lower than the first frequency y1.345Hz to 1.4kHzB zone center of gravity that is the hitting sound duration x that is the center of gravity of the B zone curved surface that is the sounding curved surface in the second regiontimex_gbButIt was selected from 10msec to 15msec from the start of soundingFirst discrimination time x_t1If larger than, it is evaluated that an internal defect exists in the concrete member near the hitting point.It is characterized by that.
[0010]
  Also,The concrete hammering sound inspection method according to the present invention detects a hammering sound generated when the surface of a concrete member is hit by the acoustic detection means, and detects analog waveform data of the detected hammering sound at a time interval Δt by the data conversion means. Sampling and digitizing the sound waveform amplitude value to convert it into digital waveform data, and analyzing the converted digital waveform data by time / frequency analysis means by time / frequency analysis means, The sound analysis data (x, y, z) comprising the frequency y of the sound and the strength z of the sound is calculated, and the sound analysis data (x, y, z) is orthogonal to the x axis and y. By discriminating the shape of the percussion surface obtained by plotting in a percussion analysis space, which is a three-dimensional coordinate space consisting of an axis and a z-axis, In concrete striking noise test method for evaluating the presence and extent of,The value of the sound hitting frequency y is equal to or lower than the second frequency y2.Centered at 86HzC zone upper end time x that is the sound hit duration x that becomes the upper end of the C zone curved surface that is the sound hitting curved surface in the third region_ecButIt was selected from 15msec to 50msec from the start of soundingSecond discrimination time x_t2In the above case, it is evaluated that there is a portion where the support state behind the concrete member is poor.It is characterized by that.
[0011]
In the concrete hammering inspection method, preferably, the hammering sound intensity data on each frequency line in the hammering sound analysis data is weighted so as to decrease as the hammering sound duration value increases. A time direction sum that is a sum of products multiplied by a time direction weighting factor to be calculated, and each time direction sum is multiplied by a frequency direction weighting factor that is weighted so as to increase as the frequency value increases. A comprehensive evaluation value that is the sum is calculated, and if the comprehensive evaluation value is equal to or less than the comprehensive evaluation discriminating value, a comprehensive evaluation is made that there is a problem with the quality of the concrete member.
[0012]
  Further, the concrete hammering inspection apparatus according to the present invention samples acoustic detection means for detecting a hammering sound generated when a surface of a concrete member is hit, and samples analog waveform data of the detected hammering sound at a time interval Δt. And a data conversion means for converting the amplitude value of the sound waveform into digital waveform data by discretizing it, and a time duration / frequency analysis of the converted digital waveform data to analyze the duration x of the sound and the frequency of the sound. Time / frequency analysis means for calculating sound analysis data (x, y, z) composed of y and sound intensity z, and x-axis orthogonal to the sound analysis data (x, y, z) Display means for visually displaying the shape of a sound-sounding curved surface obtained by plotting in a sound-sounding analysis space which is a three-dimensional coordinate space made up of a y-axis and a z-axisAnd the hitting sound that is the center of gravity of the A zone curved surface that is the hitting curved surface in the first region in which the value of the hitting sound duration x is equal to or shorter than the first hitting sound duration x1 from the start of hitting to 2 msec. A zone center-of-gravity frequency y which is frequency y _ga Discriminating frequency y selected from 1000 Hz to 4000 Hz _t The evaluation means for evaluating that there is a strength deterioration portion in the vicinity of the impact point of the concrete member.It is characterized by that.
[0013]
  Further, the concrete hammering inspection apparatus according to the present invention samples acoustic detection means for detecting a hammering sound generated when a surface of a concrete member is hit, and samples analog waveform data of the detected hammering sound at a time interval Δt. And a data conversion means for converting the amplitude value of the sound waveform into digital waveform data by discretizing it, and a time duration / frequency analysis of the converted digital waveform data to analyze the duration x of the sound and the frequency of the sound. Time / frequency analysis means for calculating sound analysis data (x, y, z) composed of y and sound intensity z, and x-axis orthogonal to the sound analysis data (x, y, z) Display means for visually displaying the shape of a sound-sounding curved surface obtained by plotting in a sound-sounding analysis space that is a three-dimensional coordinate space consisting of the y-axis and the z-axis, and the sounding frequency y B zone centroid time x but it is the hitting sound duration x of the center of gravity of B zone curved surface which is the hitting sound curved surface in the second region to 1.4kHz from 345Hz to be the first frequency y1 less _gb Is the first determination time x selected from 10 msec to 15 msec from the start of the hitting sound _t1 If larger than, it is evaluated that an internal defect exists in the concrete member near the hitting point.Evaluation methodWhenWithIt is characterized by.
  Further, the concrete hammering inspection apparatus according to the present invention samples acoustic detection means for detecting a hammering sound generated when a surface of a concrete member is hit, and samples analog waveform data of the detected hammering sound at a time interval Δt. And a data conversion means for converting the amplitude value of the sound waveform into digital waveform data by discretizing it, and a time duration / frequency analysis of the converted digital waveform data to analyze the duration x of the sound and the frequency of the sound. Time / frequency analysis means for calculating sound analysis data (x, y, z) composed of y and sound intensity z, and x-axis orthogonal to the sound analysis data (x, y, z) Display means for visually displaying the shape of a sound-sounding curved surface obtained by plotting in a sound-sounding analysis space that is a three-dimensional coordinate space consisting of the y-axis and the z-axis, and the sounding frequency y C Zone upper time x but is the hitting sound duration x of the upper end of the C zone curved surface which is the hitting sound curved surface of the third region centering 86Hz to be the second frequency y2 less _ec Is the second discrimination time x selected from 15 msec to 50 msec from the start of the hitting sound _t2 In the above case, it is characterized by comprising evaluation means for evaluating that there is a portion with a poor support state behind the concrete member.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
FIG. 1 is a block diagram showing a configuration of a concrete hammering inspection apparatus according to an embodiment of the present invention.
[0016]
As shown in FIG. 1, the concrete hammering inspection apparatus 100 includes a condenser microphone 1, a signal processing unit 2, an analysis unit 3, an image display unit 4, and a data / command input unit 5. Yes.
[0017]
The condenser microphone 1 has a vibrating membrane (not shown) and a back electrode (not shown) disposed behind the vibrating membrane, and constitutes a capacitor (capacitor). When it is vibrated, the capacitance between the vibrating membrane and the back electrode changes, and by detecting that this change appears as a change in the output voltage, the sound intensity, for example, the sound pressure is reduced. It is to be measured.
[0018]
With such a configuration, a sound (hereinafter referred to as “sounding sound”) generated when the surface of a concrete member (not shown) is struck is detected by the condenser microphone 1 and converted into an electrical signal for signal processing. It is output to part 2. Here, the condenser microphone 1 corresponds to the sound detection means in the claims. The electric signal detected by the condenser microphone 1 corresponds to the analog waveform data in the claims.
[0019]
In addition, it is necessary to perform the hit | damage of the above-mentioned concrete member so that an individual difference may not arise, for example, in the case of the upper surface of a concrete member, the weight of predetermined | prescribed mass (weight) is dropped freely from predetermined | prescribed height. Can be considered. In addition, in the case of the side surface or the lower surface of a concrete member, it is conceivable that a hammer having a predetermined mass (weight) is caused to impact the concrete member from a predetermined position. It is necessary to make adjustments so as to always carry out under the condition of constant kinetic energy by using various actuators (not shown) or a striking mechanism (not shown) using a spring elastic force.
[0020]
Although not shown, the signal processing unit 2 includes a preamplifier (preamplifier) on the input side. This is because the condenser microphone 1 has a high impedance and thus needs to convert the impedance.
[0021]
Although not shown, the signal processing unit 2 has an analog / digital converter on the output side of a preamplifier (preamplifier). This analog-to-digital converter performs temporal sampling by sampling the amplitude value of analog waveform data that is continuous in time (operation to capture the amplitude value of the wave as an input signal at certain time intervals). The data is converted into discretized quantum digital waveform data. Although an appropriate value can be adopted as the sampling frequency, 44.1 kHz (kilohertz) is adopted in the concrete hammering inspection apparatus 100 shown in FIG. Here, an analog / digital converter (not shown) of the signal processing unit 2 corresponds to the data conversion means in the claims.
[0022]
The analysis unit 3 is a part that analyzes the digital waveform data sent from the signal processing unit 2, generates data for evaluating the presence / absence and degree of deterioration of the concrete member, and outputs the data to the subsequent stage. Although not shown, the analysis unit 3 includes a CPU (Central Processing Unit), a main storage unit, a temporary storage unit, an input / output control unit, and the like. It is configured to be able to perform detection and time / frequency analysis.
[0023]
Although not shown, the CPU has an internal bus which is a signal line for transmitting and receiving current (signals) inside the CPU. The internal bus includes an arithmetic unit, a register, and a clock generator. A command processing unit and the like. The arithmetic unit in the CPU generally performs four arithmetic operations (addition, subtraction, multiplication, and division) or various logical operations (logical product, logical sum, negation, exclusive) on various data stored in the register. This is a portion for performing processing such as logical sum or data comparison or data shift. In general, the result of the processing is stored in a register.
[0024]
The register is generally a part for storing one word of data. Usually, a plurality of registers are provided in the CPU. The clock generator is a part that generates a clock signal (clock signal) for synchronizing the time of each part of the CPU. The CPU operates based on this clock signal. The instruction processing unit is a part that controls and processes fetching, decoding, and execution of instructions to be executed by the arithmetic unit and the like.
[0025]
Although not shown, the main storage unit has a hard disk device (HDD), a ROM (Read Only Memory), etc., and a control program for controlling the CPU and various data used by the CPU. Etc. are stored. Although not shown, the hard disk device has a disk-shaped magnetic disk therein, and the magnetic disk is rotated by a disk drive mechanism, and the magnetic head is moved to an arbitrary position of the magnetic disk by a head drive mechanism. The data is recorded by magnetizing the magnetic film on the surface of the magnetic disk with a write current from the magnetic head, and flows to the coil of the magnetic head when the magnetic head moves over the magnetized magnetic film. It is a device that reads recorded data by detecting current. The ROM is generally composed of a semiconductor chip or the like.
[0026]
The above control program is a character in which processing procedures such as instructions for causing the CPU to execute image processing, analysis calculation, etc. are described in a predetermined program language in addition to basic software of the CPU such as an OS (Operating System). Or a set of symbols.
[0027]
Although not shown, the temporary storage unit has a RAM (Random Access Memory) and the like, and temporarily stores data in the middle of calculation by the CPU. The RAM is generally composed of a semiconductor chip or the like.
[0028]
The input / output control unit is also called an interface (I / O), and has a signal line or a bus as a set thereof, various connectors, various ports, a read / write control mechanism of the hard disk device, and the like. It is a part for sending and receiving signals and signals from each device.
[0029]
The data / command input unit 5 includes a keyboard, a trackball, a pointing device including a touch pad or a stick pointer, a touch panel device, and the like, and inputs a command signal to the CPU, data processed by the CPU, and the like from the outside. It is a part to do.
[0030]
The image display unit 4 includes a CRT (Cathode Ray Tube) monitor, a liquid crystal display panel, a plasma display device, and the like. The calculation results of the CPU and processed data are displayed on the screen as images and characters. This is a display part and corresponds to the display means in the claims.
[0031]
Moreover, this concrete hammering test | inspection apparatus 100 is provided with the output part (not shown). The output unit has a printer, an external output terminal, a communication device such as a modem, a LAN (Local Area Network) port, etc., and prints the CPU calculation results and processed data on paper or the like, or an electrical signal As a part to be output or transmitted to the outside. If an external recording device such as a flexible disk (FD) device, a magneto-optical disk device, a PC card device or the like is connected to the external output terminal, the recorded hitting sound data, the result data processed by the CPU, etc. are recorded on a disk or the like. Can be recorded on a recording medium and taken out to the outside.
[0032]
Next, the process performed by the analysis unit 3 will be described in more detail. First, peak value detection is performed as follows. First, for example, a ring buffer memory (not shown) is provided as a temporary storage unit of the analysis unit 3. The ring buffer memory is a storage device that repeatedly accumulates and stores data for a predetermined time (for example, 2 milliseconds) and repeatedly outputs the data after the predetermined time has elapsed. The digital waveform data output from the signal processing unit 2 is first input to this ring buffer memory. The CPU (not shown) of the analysis unit 3 monitors the output from the ring buffer memory and searches for a peak value at the time of hitting (the moment when the weight or hammer hits the concrete member surface).
[0033]
In this case, the portion where the peak at the time of impact protrudes from the preceding and following data values, and the data is taken from the portion where the peak value is larger than a certain value. In the case of the present embodiment, data is taken in from a point where the value is larger than 25% of the peak maximum value. This is because, if data is taken from a state where it is buried in ambient noise, an error in time / frequency analysis described later becomes large.
[0034]
Next, the time / frequency analysis will be described in more detail. Frequency analysis is generally used as a method for analyzing waveform data such as sound waves and vibrations. Frequency analysis is a technique for analyzing frequency characteristics among the characteristics of waveform data that changes over time. As a method of frequency analysis, Fourier transform is generally used. In the Fourier transform, time domain data such as waveform data is frequency domain (frequency domain) data, for example, the frequency is taken on the horizontal axis, and the sound intensity level value or vibration level value at each frequency is taken on the vertical axis. This is a method of converting into a plotted graph (frequency spectrum) or the like. By looking at this frequency spectrum, it is possible to analyze at what frequency the sound and vibration are dominant. As a technique for analyzing the digitized digital waveform data, FFT (Fast Fourier Transform) which is a calculation algorithm that further speeds up the Fourier transform is often used.
[0035]
However, the frequency analysis by FFT is based on the assumption that the spectral characteristics of the waveform data to be analyzed are in a steady state, and cannot be used when the spectral characteristics change with time. Therefore, a technique (hereinafter referred to as “time / frequency analysis”) for capturing and analyzing the temporal change of the frequency spectrum is required.
[0036]
The time / frequency analysis executed in the analysis unit 3 of the present embodiment is referred to as “inverse wavelet transform (inverse wavelet transform)”. Hereinafter, the contents of the inverse wavelet transform will be described.
[0037]
The wavelet is a function as shown in FIG. 2 and means a “small wave” localized in time when x is time. Hereinafter, this wavelet is expressed by a function ψ (x).
[0038]
When this wavelet is used, for example, a function f (x) as shown in FIG. 3A, that is, a portion P1 of a waveform (sine wave) whose amplitude value and frequency change with time x is shown in FIG. As shown in (), the wavelet W1 can be cut out to correspond. In this case, the variable x of the original wavelet ψ (x) shown in FIG. 2 is replaced with (x−b) / a, and a real number so as to express the amplitude value and frequency in the part P1 of the function f (x) well. Select a and b.
[0039]
Thus, the wavelet can be used as a unit for cutting out a part of the waveform signal. The original wavelet ψ (x) in this case is called a mother wavelet or an analysis wavelet. Various function forms have been proposed for the mother wavelet. For example, Haar wavelet, Gabor wavelet, Malver wavelet, Morlet wavelet, so-called Mexican hat, so-called French hat, Shannon wavelet, Meyer wavelet, Daubechies wavelet, Symlet, Coiflet, Spline wave. In the analysis unit 3 of the present embodiment, a function called Mother-Wavelet of Battle-Lemarie, which is a kind of spline wavelet, is employed.
[0040]
Similarly, a part P2 of the function f (x) in FIG. 3A can be associated with the wavelet W2 as shown in FIG. 3C, and the function f ( A part P3 of x) can be made to correspond with the wavelet W3 as shown in FIG. 3D, and a part P4 of the function f (x) in FIG. 3A is shown in FIG. Can be matched with Wavelet W4.
[0041]
In this way, wavelet transform can be defined by the following equation (1).
[0042]
[Expression 1]

[0043]
In the above equation (1), the function ψ part of the integral term represents the complex conjugate function of the function ψ (x). Conversely, the original waveform signal f (x) can be restored from the above equation (1). In this case, the inverse transformation of the wavelet transformation described above, that is, the inverse wavelet transformation (Inverse Wavelet Transform) is performed. The inverse wavelet transform is defined by the following equation (2).
[0044]
[Expression 2]

[0045]
After performing wavelet transform, if inverse wavelet transform is performed for each order (each frequency), as shown in FIG. 4, the sound is hit on a plane with time x as the horizontal axis and frequency y as the vertical axis. The function f (x) representing the intensity z of the signal can be decomposed and restored for each frequency. For example, in FIG. 4, the function g1 (x) is used as a function component at the frequency f1, the function g2 (x) is used as the function component at the frequency f2, the function g3 (x) is used as the function component at the frequency f3, and the frequency f4. The function g4 (x) can be obtained as the function component in.
[0046]
As described above, the analysis unit 3 of the present embodiment employs a Battle-Lemarie mother wavelet as the mother wavelet. However, the function g1 (x) at each frequency f1 and the like is thereby adopted. For example, a waveform such as a sine waveform (attenuating harmonic vibration) in which the amplitude value increases at first, and after the amplitude value reaches its peak, the amplitude value generally attenuates over time. When z is z, the following formula (3)
z = A · exp (−kx) · sin (ωx + δ) (3)
A function close to. Here, exp represents a natural exponential function, and A, k, and ω all represent positive real numbers. δ is a real number.
[0047]
In the analysis unit 3 of the present embodiment, it is assumed that there is a difference between individuals when a concrete member is hit (when there is a difference in sound intensity of the collected microphone), and this is normalized to prevent errors. A processing course is in place. That is, the amplitude value when the amplitude value becomes maximum in the waveform at each frequency after the inverse wavelet transform is set to a predetermined value (100 in the present embodiment), and the entire waveform is processed to be similar. .
[0048]
Next, the analysis unit 3 of the present embodiment calculates a value called “effective value” in the waveform at each frequency after the inverse wavelet transform. This effective value is obtained by calculating all the waveform amplitude maximum values A1, A2,... In the waveform at each frequency after the inverse wavelet transform, and three consecutive (adjacent) values, for example, A1, A2, and A3, The average value of (A1 + A2 + A3) / 3 is calculated, and each of these average values is assigned to the position of the first maximum amplitude value of the three sets, for example, the position of A1 in the case of the set of A1, A2, and A3. Plot it. Next, a smooth curve is obtained by interpolating between the discrete values obtained in this way by a method called “cubic spline interpolation”. Cubic spline interpolation is an interpolation method in which adjacent points are continuously connected by a second derivative.
[0049]
Through the above processing, although there are some irregularities on the horizontal line of each frequency after the inverse wavelet transform (hereinafter referred to as “frequency line”), it increases at first, and after reaching the peak A curve is drawn that generally decays over time x. Hereinafter, this curve is referred to as a “sounding sound effective curve”. A smooth curved surface can be obtained by performing interpolation such as the above-described cubic spline interpolation in the vertical axis direction (frequency direction) on the basis of these hitting sound effective curves. This curved surface is a three-dimensional orthogonal coordinate space (hereinafter referred to as “hitting sound analysis space”) in which the duration of the hitting sound is the x axis, the hitting frequency is the y axis, and the strength of the hitting sound is the z axis. It is drawn in the following, and is hereinafter referred to as “sounding curved surface”.
[0050]
FIG. 5 is a conceptual diagram showing a sounding curved surface in the sounding analysis space displayed on the image display unit 4 of the concrete sounding inspection apparatus 100 shown in FIG. Further, the sounding surface is on the xy plane (a plane determined by the sounding duration x-axis and the sounding frequency y-axis; hereinafter referred to as “sounding duration / frequency plane”). You may connect and display the location where z value is equal by a contour line. FIG. 6 is a conceptual diagram for explaining a characteristic shape when evaluating deterioration of a concrete member among the diagrams in which z values are displayed as contour lines on the xy plane.
[0051]
The applicants detect the sound generated when hitting the surface of a concrete member (not shown) with the above-described condenser microphone 1, perform signal processing with the signal processing unit 2, and then perform analysis with the analysis unit 3. As a result of performing a lot of laboratory experiments and field tests to display the sounding curved surface on the image display unit 4 by performing time / frequency analysis, the shape when the sounding curved surface is displayed so that the z value is displayed in a contour line on the xy plane And a certain relationship between the deterioration of concrete members and the concrete member.
[0052]
That is, as shown in FIG. 6, when there is a deteriorated portion in the concrete member, “A zone”, “B zone”, “C zone” are included in the sound-sounding curved surface according to the type and degree of the deterioration. ”Appears as a characteristic area. These will be described below.
[0053]
The A zone shown in FIG. 6 is an area in the xy plane where the duration x of the hit sound is short and the frequency y is high, that is, above the vertical axis (frequency axis) of the xy plane, in other words, the xy plane. Appears near the upper left of. As a result of the experiment, when the strength of the concrete member was high, the A zone appeared near the y axis and considerably above the xy plane. On the other hand, when the strength of the concrete member is low, the A zone is near the y axis, but the position in the y direction is low. And it became clear by experiment that the height position of the y direction of A zone will become a still lower position when the intensity | strength of a concrete member becomes very low. From this, it is considered that the frequency (y value) at the position of the A zone indicates the degree of strength of the concrete member. According to the experimental results, when the compressive strength of the concrete member is about 20 MPa (megapascal), the frequency y of the A zone is about 1.4 to 11.0 kHz. Further, looking at the duration x of the hitting sound, for example, when the frequency is 2.8 kHz, the maximum value is reached in about 1 msec from the start of the hitting sound data fetching, and then the peak ends in 1 msec. Therefore, it is considered that the time range of the A zone should be about 2 msec from the time point of x = 0 (time point of hitting sound data acquisition).
[0054]
Next, in the B zone shown in FIG. 6, in the xy plane, the hitting sound duration x is slightly short and the frequency y is almost in the middle, that is, the middle slightly close to the vertical axis (frequency axis) of the xy plane. In other words, in the vicinity of the center of the left half of the xy plane. As a result of the experiment, at a certain point inside the concrete member, mainly the coarse aggregate is left behind, and the fine aggregate and cement part flowed out to become a void, so-called `` junka '' When there was a part called, the B zone often appeared below the A zone. When actually listening to the B zone sound, it sounds like “gush”. From this, when this B zone appears, it is thought that it has shown that some defects, such as a junker and a cold joint, exist in the inside of a concrete member. According to the experimental results, when the compressive strength of the concrete member is about 20 MPa and there is a jumper inside, the frequency y of the B zone is about 345 Hz to 1.4 kHz, and the duration x of the hitting sound is about 15 msec. It was.
[0055]
Next, in the C zone shown in FIG. 6, in the xy plane, the hitting sound duration x extends over almost the entire region and the frequency y is low, that is, the horizontal axis (sounding duration time axis of the xy plane). ) Along the lower part, in other words, in the lower half of the xy plane. As a result of the experiment, when the concrete member is supported, for example, when the lower part of the concrete member is supported, the entire lower surface is not supported, but only a part of the concrete member is supported. When both ends of the member are simply supported, a remarkable C zone extending in the lateral direction (x-axis direction) often appears. Further, it has been found that the length of the C zone in the x-axis direction is shortened when the supporting conditions of the concrete member are improved and, for example, the number of supporting portions in the lower portion of the concrete member is increased. From this, it is considered that this C zone indicates the degree of support state behind the concrete member. According to the experimental results, when the concrete member has a compressive strength of about 20 MPa and a simple support condition, the C zone is an area centered at a frequency of about 86 Hz, and the hitting sound duration x remains up to about 50 msec.
[0056]
Based on the above, the analysis unit 3 of the concrete hammering inspection apparatus 100 detects the presence of the above-described A, B, and C zones, and determines and evaluates the degree thereof. Hereinafter, the content will be described in detail.
[0057]
First, detection of the A zone and its evaluation will be described. In the analysis by the analysis unit 3, “A zone appears within a time range of 2 msec from the start of sounding (at time x = 0)” in the analysis by the analysis unit 3. And the following calculation and processing were performed.
[0058]
First, with respect to each of the striking sound effective curves on the frequency lines (lines parallel to the x-axis) that are horizontal lines of the respective frequencies, the integrated value (x = 0) from the beginning of striking (x = 0) to x = 2 msec. And the area of the substantially trapezoidal portion between the effective sounding curve between 2 msec and the xy plane). Thus, for example, the area for the frequency f1 is s1, the area for the frequency f2 is s2, the area for the frequency f3 is s3,..., The area for the frequency fi is si,. A value such that the area in the case is sn-1 and the area in the case of the frequency fn is sn is obtained.
[0059]
Next, the sum total v1 = Σsi of these areas is obtained. Next, a sum v2 = Σ (si × fi) of products (si × fi) obtained by multiplying the area si of each frequency by the frequency fi is obtained. Then, a quotient v3 = (v2 / v1) obtained by dividing the value v2 by the value v1 is calculated. This value v3 represents a virtual frequency, which is a frequency y corresponding to the center of gravity of the A zone in FIG._ga(Hereinafter referred to as “A zone barycentric frequency”). Further, the time of 2 msec from the start of the hitting sound corresponds to the first hitting sound duration x1 in FIG. Further, the time region from the start of the hitting sound to 2 msec corresponds to the first region in the claims.
[0060]
Therefore, from the nature of the A zone, the A zone centroid frequency y_gaIs a certain frequency value y_tIf it is lower, the strength of the concrete member in the vicinity of the impact point is considered to be lower than a predetermined value. The frequency value y so that the predetermined value in this case is equal to the design strength of the concrete_tIs set, it can be determined that “the strength has deteriorated” near the striking point of the concrete member. Hereafter, y at this time_tIs called “discrimination frequency”. Discrimination frequency y_tIs considered to be a value in the range of 1000 to 4000 Hz (1 to 4 kHz), for example.
[0061]
In the analysis unit 3 of the concrete hammering inspection apparatus 100 of the present embodiment, image data of an evaluation screen as shown in FIG. 8A is created and output to the image display unit 4 for display. That is, as “A zone evaluation”, a red bar C1, a yellow bar C2, and a green bar C3 are displayed adjacent to each other. Here, the red bar C1 represents a dangerous (deteriorated) range. Further, the yellow bar C2 represents a range to be watched (warned). Further, the green bar C3 represents a good range (no risk of deterioration).
[0062]
Here, the boundary value between the red bar C1 and the yellow bar C2 is set to, for example, 3000 (Hz). The value of the boundary between the yellow bar C2 and the green bar C3 is set to 6000 (Hz), for example. Among these, the boundary line having a value of 3000 represents a determination frequency that is a criterion for determining deterioration. The value v3 calculated as described above (or the A zone center-of-gravity frequency y)_ga) Is displayed in the score column W1, for example, “5246”. Also, a black evaluation line L1 is displayed at a position corresponding to the numerical value in the score column W1. The evaluation line L1 may be displayed blinking so as to stand out. In the case of FIG. 8A, it is indicated that the evaluation line L1 is in the range of the yellow bar C2. By such an image display, the user of the concrete hammering test apparatus 100 can judge the degree of deterioration of the strength of the concrete member numerically or sensibly.
[0063]
Next, detection of B zone and its evaluation will be described. In the evaluation of the B zone, the following calculation and processing were performed.
[0064]
The maximum value is detected for the effective sounding curve on a frequency line (a line parallel to the x-axis) that is a horizontal line at each frequency. For example, the maximum value of the effective sounding curve for the frequency f1 is h1. Next, the elapsed time from h1 when the value is attenuated to a value that is a predetermined ratio (5% in the case of the present embodiment) with respect to h1 on the effective sounding curve is expressed as “effective decay time”. ”And t_d1It will be expressed as Similarly, the effective decay time t in the case of the frequency f2._d2Hereinafter, similarly, the effective decay time t at the i-th frequency fi_diAnd the effective decay time t at the last (nth) frequency fn_dnTo ask.
[0065]
Next, a weighted average value of these effective decay times v4 = (Σt_di) / N. This value represents a virtual time, which is a time x corresponding to the center of gravity of the B zone in FIG._gb(Hereinafter referred to as “B zone barycenter time”). The B zone should appear in a region (second region) below the first frequency y1, but the effective decay time t in a high frequency region._diSince the value of is considered to be very small, the component in the high frequency region is the B zone centroid time x_gbAs a result, the weighted average value v4 of the effective decay time is considered to be in the region below the first frequency y1.
[0066]
Therefore, from the nature of the B zone, the B zone centroid time x_gbIs a time value x_t1If it is larger than that, it is considered that a defect exists in the vicinity of the striking point of the concrete member. The predetermined value in this case is a time value x that is equal to the case where there is a jumper inside or the case where there is a cold joint inside._t1Is set, it can be determined that “there is an internal defect” near the striking point of the concrete member. Hereafter, x at this time_t1Is referred to as “first discrimination time”. First discrimination time x_t1Is considered to be a value in the range of 10 to 15 msec, for example.
[0067]
In the analysis unit 3 of the concrete hammering inspection apparatus 100 of the present embodiment, image data of an evaluation screen as shown in FIG. 8B is created and output to the image display unit 4 for display. That is, as the “B zone evaluation”, a green bar C4, a yellow bar C5, and a red bar C6 are displayed adjacent to each other. Here, the red bar C6 represents a dangerous range (with an internal defect). Further, the yellow bar C5 represents a range to be watched (warned). The green bar C4 represents a good range (no risk of internal defects).
[0068]
Here, the value of the boundary between the red bar C6 and the yellow bar C5 is set to 8 (msec), for example. The boundary value between the yellow bar C5 and the green bar C4 is set to 3 (msec), for example. Among these, the boundary line having a value of 8 represents a first determination time that is a determination reference for internal defects. Then, the value v4 (or B zone centroid time x calculated as described above)_gb) Is displayed in the score column W2, for example, “2.5”. Also, a black evaluation line L2 is displayed at a position corresponding to the numerical value in the score column W2. The evaluation line L2 may be displayed blinking so as to stand out. FIG. 8B shows that the evaluation line L2 is in the range of the green bar C4. By such an image display, the user of the concrete hammering inspection apparatus 100 can judge the degree of internal defects of the concrete member numerically or sensibly.
[0069]
Next, detection of C zone and its evaluation will be described. In the evaluation of the C zone, the following calculation and processing were performed.
[0070]
The maximum value is detected for the effective sounding curve on a frequency line (a line parallel to the x-axis) that is a horizontal line at each frequency. For example, the maximum value of the effective sounding curve for the frequency f1 is h1. Next, the elapsed time from h1 when the value is attenuated to a value that is a predetermined ratio (5% in the case of the present embodiment) with respect to h1 on the effective sounding curve is expressed as “effective decay time”. ”And t_d1It will be expressed as Similarly, the effective decay time t in the case of the frequency f2._d2Hereinafter, similarly, the effective decay time t at the i-th frequency fi_diAnd the effective decay time t at the last (nth) frequency fn_dnTo ask.
[0071]
Next, among these effective decay times, the maximum t_dmaxIs detected. This value represents a virtual time, which is a time x corresponding to the upper end (right end) of the C zone in FIG._ec(Hereinafter, referred to as “C zone upper end time”). The C zone should appear in the region (third region) below the second frequency y2, but the effective decay time t in the high frequency region._diSince the value of is considered to be very small, the component in the high frequency region is the C zone upper end time x_ecIt is considered that the region of the second frequency y2 or less is considered as a result.
[0072]
Therefore, due to the nature of the C zone, the C zone upper end time x_ecIs a time value x_t2If it is larger than that, it is considered that there is a portion with a poor support state in the vicinity of the impact point of the concrete member. The predetermined value in this case is equal to a time value x such that the predetermined value is equal to the case where a hollow portion exists inside_t2Is set, it can be determined that “the supporting state is poor” in the vicinity of the striking point of the concrete member. Hereafter, x at this time_t2Is referred to as “second discrimination time”. Second discrimination time x_t2Is considered to be a value in the range of 15 to 50 msec, for example.
[0073]
In the analysis unit 3 of the concrete hammering inspection apparatus 100 of the present embodiment, image data of an evaluation screen as shown in FIG. 8C is created and output to the image display unit 4 for display. That is, as the “C zone evaluation”, a green bar C7, a yellow bar C8, and a red bar C9 are displayed adjacent to each other. Here, the red bar C9 represents a dangerous (poor support state) range. Further, the yellow bar C7 represents a range to be watched (warned). Further, the green bar C6 represents a good range (no fear of poor support).
[0074]
Here, the value of the boundary between the red bar C9 and the yellow bar C8 is set to 20 (msec), for example. The boundary value between the yellow bar C7 and the green bar C6 is set to 10 (msec), for example. Among these, a boundary line with a value of 20 represents a second determination time that is a determination criterion for poor support. The C zone upper end time x calculated as described above_ecIs displayed in the score column W3 as “23.1”, for example. Further, a black evaluation line L3 is displayed at a position corresponding to the numerical value in the score column W3. The evaluation line L3 may be displayed blinking so as to stand out. In the case of FIG. 8C, it is indicated that the evaluation line L3 is in the range of the red bar C9. With such an image display, the user of the concrete hammering test apparatus 100 can determine the degree of poor support of the concrete member numerically or sensibly.
[0075]
Next, comprehensive evaluation of the hammering test will be described. In the comprehensive evaluation, the following calculations and processing were performed.
[0076]
First, a discrete value before performing spline interpolation is read out with respect to a sounding effective curve on a frequency line (a line parallel to the x axis) that is a horizontal line at each frequency. Next, all the discrete values in a period of 40 msec from the starting sounding point (x = 0) are summed up for a certain frequency. Next, this sum is summed for all (n) frequencies. This total value is S_{f, 40}And Next, each of the discrete values before the spline interpolation is expressed as the sum S_{f, 40}Normalization is performed by dividing by.
[0077]
Next, in the time axis (x-axis) direction, the value is “+1” at the sounding start time (x = 0), and the value is “−” at the time 40 msec after the sounding start time (x = 0). 1 ”(hereinafter referred to as“ time direction weighting coefficient straight line ”). That is, the weighting coefficient in the time direction decreases as the time value increases, and finally becomes a negative value.
[0078]
On a frequency line (a line parallel to the x-axis) that is a horizontal line at each frequency, the discrete value is multiplied by the value of the time direction weighting coefficient straight line at the position corresponding to the value to obtain a “weighted discrete value”. Then, the sum of the weighted discrete values is calculated for each frequency line at each frequency. That is, in ascending order of frequency, the time direction sum that is the sum of the weighted discrete values at the frequency f1 is σ1, the time direction sum that is the sum of the weighted discrete values at the frequency f2 is σ2, and so on. The sum in the time direction, which is the sum of the weighted discrete values in the case of the frequency fi, is σi,..., The sum in the time direction, which is the sum of the weighted discrete values in the case of the frequency fn−1, is σn−1, and The sum in the time direction that is the sum of the weighted discrete values is represented by σn.
[0079]
Next, the frequency direction weighting coefficient kn at the highest frequency fn is set to 1, the frequency direction weighting coefficient kn-1 at the next highest frequency fn-1 is set to 1/2, and the next highest frequency fn- The frequency direction weighting coefficient kn-2 in the case of 2 is set to 1/4, and the frequency direction weighting coefficient ki in the case of the frequency fi is set to 1 / (2ⁿⁱ), ..., the frequency direction weighting coefficient k3 in the case of the frequency f3 is 1 / (2^n-3) And the frequency direction weighting coefficient k2 for the frequency f2 is 1 / (2^n-2) And the frequency direction weighting coefficient k1 for the lowest frequency f1 is 1 / (2^n-1). That is, the weighting coefficient ki in the frequency direction increases with a positive value as the frequency increases.
[0080]
Next, the time direction sum σi in the case of the frequency fi described above is multiplied by a weighting coefficient ki in the frequency direction to obtain the sum of these products for all (n) frequencies, and this is used as a comprehensive evaluation value. . And it evaluates that a concrete member is a favorable state, so that a comprehensive evaluation value is large. That is, in the comprehensive evaluation, the weighting is increased so that the evaluation becomes smaller as the hitting sound duration is longer, and the weighting is increased so that the evaluation becomes higher as the frequency is higher.
[0081]
In the analysis unit 3 of the concrete hammering inspection apparatus 100 of the present embodiment, image data of an evaluation screen as shown in FIG. 8D is created and output to the image display unit 4 for display. That is, as the “total evaluation”, a red bar C10, a yellow bar C11, and a green bar C12 are displayed adjacent to each other. Here, the red bar C10 represents a dangerous range (there is a problem with the quality of the concrete member). Further, the yellow bar C11 represents a range to be watched (warned). Further, the green bar C12 represents a good range (no problem in the quality of the concrete member).
[0082]
Here, the boundary value between the red bar C10 and the yellow bar C11 or the boundary value between the yellow bar C11 and the green bar C12 is set to an appropriate value. For example, the boundary value between the red bar C10 and the yellow bar C11 may be a negative value. Then, the comprehensive evaluation value calculated as described above is displayed in the score column W4 as “32”, for example. Further, a black evaluation line L4 is displayed at a position corresponding to the numerical value in the score column W4. The evaluation line L4 may be displayed blinking so as to stand out. In the case of FIG. 8D, it is shown that the evaluation line L4 is in the range of the green bar C12. With such an image display, the user of the concrete hammering test apparatus 100 can judge the degree of comprehensive evaluation of the concrete member numerically or sensibly.
[0083]
By comprising as mentioned above, the concrete hammering test | inspection apparatus 100 of this embodiment has the following advantages.
[0084]
A concrete member is struck under certain conditions, the sound generated at that time is processed with a predetermined logic, and evaluation values are calculated to evaluate strength deterioration. In addition, there is an advantage that there is no individual difference (difference in the results) of the person in charge of the diagnosis in the diagnosis result, and quantitative evaluation can be easily made as the diagnosis result.
[0085]
In the above embodiment, the CPU (not shown) of the analysis unit 3 corresponds to time / frequency analysis means and evaluation means in the claims.
[0086]
The present invention is not limited to the above embodiments. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.
[0087]
For example, in the above-described embodiment, the condenser microphone is described as an example of the acoustic detection unit. However, the present invention is not limited to this, and the acoustic detection unit of another configuration, such as an electret microphone, may be used. Good.
[0088]
In the above-described embodiment, wavelet inverse transformation has been described as an example of the time / frequency analysis method. However, the present invention is not limited to this, and other time / frequency analysis methods such as a short time Inverse Fourier transform (STFT: Short Time Fourier Transform), Wigner distribution (WD), or the like may be employed.
[0089]
【The invention's effect】
As described above, according to the present invention, the sound of the concrete member is detected by the acoustic detection means, the data is converted to digital waveform data by the data conversion means, and the time / frequency analysis is performed by the time / frequency analysis means. Is used to calculate the percussion analysis data (x, y, z) comprising the percussion duration x, percussion frequency y, and percussion intensity z, and plot the percussion analysis data in a three-dimensional percussion analysis space. By determining the shape and the extent of deterioration of the concrete member by discriminating the shape of the sounding curved surface obtained in this way, the concrete member is struck under certain conditions, and the struck sound generated at that time is set to a predetermined level. Since it is processed logically and evaluation values are calculated to evaluate strength deterioration, etc., the inspector does not need any particular experience, and there may be individual differences (individual results) among inspectors in the diagnosis results. Ku, it is possible to easily make a quantitative evaluation as a diagnostic result, there is an advantage.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a concrete hammering inspection apparatus according to an embodiment of the present invention.
2 is a diagram illustrating an example of a wavelet used for wavelet inverse transformation in an analysis unit of the concrete hammering inspection apparatus illustrated in FIG. 1;
FIG. 3 is a conceptual diagram illustrating the relationship between the waveform data of a hit sound and a wavelet.
FIG. 4 is a conceptual diagram illustrating the relationship between the waveform data of the hit sound and the inverse wavelet transform.
FIG. 5 is a conceptual diagram showing a hammering curved surface in a hammering analysis space displayed on the image display unit of the concrete hammering inspection apparatus shown in FIG. 1;
6 is a diagram for evaluating deterioration of a concrete member in a diagram in which a percussion surface displayed on an image display unit of the concrete percussion inspection apparatus shown in FIG. 1 is displayed on a contour line on a percussion duration / frequency plane. It is a conceptual diagram explaining the characteristic shape.
7 is a conceptual diagram for explaining an evaluation method of zones A to C in the concrete hammering inspection apparatus shown in FIG. 1. FIG.
FIG. 8 is a conceptual diagram showing an example of an evaluation screen for a sound test result displayed on the image display unit of the concrete sound test apparatus shown in FIG. 1;
[Explanation of symbols]
1 Condenser microphone
2 Signal processor
3 Analysis Department
4 Image display area
5 Data / command input section
100 Concrete impact sound inspection system

Claims (7)

The sound detection means detects the hitting sound generated when the surface of the concrete member is hit, samples the analog waveform data of the detected hitting sound at the time interval Δt by the data conversion means, and discretizes the sound waveform amplitude value. The digital waveform data is converted into digital waveform data, and the converted digital waveform data is subjected to time / frequency analysis by a time / frequency analysis means, whereby the hitting sound duration x, the hitting frequency y, and the strength of the hitting sound. The sound analysis data (x, y, z) consisting of z is calculated, and the sound analysis data (x, y, z) is calculated in a three-dimensional coordinate space consisting of the x axis, the y axis and the z axis which are orthogonal to each other. concrete to assess the presence and extent of deterioration of the concrete member by determining the shape of the hitting sound curved surface obtained by plotting the certain striking sound analysis space In the inspection method,
The sounding frequency y that is the center of gravity position of the A zone curved surface that is the sounding curved surface in the first region in which the value of the sounding duration x is equal to or shorter than the first sounding duration x1 from the start of the sounding to 2 msec. a zone centroid frequency y _ga is lower than the determination frequency y _t selected from among 4000Hz from 1000Hz is characterized by evaluating the strength degradation point exists in the vicinity of the striking point of the concrete member is Concrete hammering inspection method. The sound detection means detects the hitting sound generated when the surface of the concrete member is hit, samples the analog waveform data of the detected hitting sound at the time interval Δt by the data conversion means, and discretizes the sound waveform amplitude value. The digital waveform data is converted into digital waveform data, and the converted digital waveform data is subjected to time / frequency analysis by a time / frequency analysis means, whereby the hitting sound duration x, the hitting frequency y, and the strength of the hitting sound. The sound analysis data (x, y, z) consisting of z is calculated, and the sound analysis data (x, y, z) is calculated in a three-dimensional coordinate space consisting of the x axis, the y axis and the z axis which are orthogonal to each other. Concrete punching for evaluating the presence and extent of deterioration of the concrete member by discriminating the shape of the hammering curved surface obtained by plotting in a certain hammering sound analysis space In the inspection method,
B which is the sound hit duration x which is the barycentric position of the B zone curved surface which is the sound hitting curved surface in the second region from 345 Hz to 1.4 kHz where the value of the sound hitting frequency y is equal to or lower than the first frequency y1. When the zone center-of-gravity time x _gb is larger than the first determination time x _t1 selected from 10 msec to 15 msec from the start of the hitting sound, it is evaluated that an internal defect exists in the concrete member near the hitting point. A concrete impact sound inspection method. The sound detection means detects the hitting sound generated when the surface of the concrete member is hit, samples the analog waveform data of the detected hitting sound at the time interval Δt by the data conversion means, and discretizes the sound waveform amplitude value. The digital waveform data is converted into digital waveform data, and the converted digital waveform data is subjected to time / frequency analysis by a time / frequency analysis means, whereby the hitting sound duration x, the hitting frequency y, and the strength of the hitting sound. The sound analysis data (x, y, z) consisting of z is calculated, and the sound analysis data (x, y, z) is calculated in a three-dimensional coordinate space consisting of the x axis, the y axis and the z axis which are orthogonal to each other. Concrete punching for evaluating the presence and extent of deterioration of the concrete member by discriminating the shape of the hammering curved surface obtained by plotting in a certain hammering sound analysis space In the inspection method,
C zone upper end time that is the sound hit duration x that is the upper end of the C zone curved surface that is the sounding curved surface in the third region centered at 86 Hz where the value of the sounding frequency y is equal to or lower than the second frequency y2. When x _ec is equal to or longer than a second determination time x _t2 selected from 15 msec to 50 msec from the start of sounding, it is evaluated that there is a portion where the support state behind the concrete member is poor. Concrete hammering inspection method. In the concrete hammering test method according to any one of claims 1 to 3 , as the hammering duration value increases in each of the hammering sound intensity data on each frequency line in the hammering analysis data. A frequency direction weighting coefficient that calculates a sum in the time direction that is a sum of products multiplied by a time direction weighting coefficient that is weighted so as to decrease, and weights each time direction sum so as to increase as the frequency value increases. And calculating a comprehensive evaluation value, which is a sum of products multiplied by, and comprehensively evaluating that there is a problem in the quality of the concrete member when the comprehensive evaluation value is less than or equal to the comprehensive evaluation discriminant value. Sound inspection method. A sound detecting means for detecting a hitting sound generated when hitting the surface of a concrete member, and analog waveform data of the detected hitting sound are sampled at a time interval Δt and digitalized by discretizing a sound hitting waveform amplitude value. A data conversion means for converting into waveform data, and a percussion sound composed of the percussion time duration x, the percussion frequency y, and the percussion intensity z by performing time / frequency analysis on the converted digital waveform data. Time / frequency analysis means for calculating the analysis data (x, y, z) and the hit sound analysis data (x, y, z) in a three-dimensional coordinate space composed of the x-axis, y-axis, and z-axis orthogonal to each other. Display means for visually displaying the shape of the percussion surface obtained by plotting in a percussion analysis space;
The sounding frequency y that is the center of gravity position of the A zone curved surface that is the sounding curved surface in the first region in which the value of the sounding duration x is equal to or shorter than the first sounding duration x1 from the start of the sounding to 2 msec. If a zone centroid frequency y _ga is lower than the determination frequency y _t selected from among 4000Hz from 1000Hz is, a evaluation means for evaluating the strength degradation point exists in the vicinity of the striking point of said concrete member Concrete hammering inspection device characterized by that. A sound detecting means for detecting a hitting sound generated when hitting the surface of a concrete member, and analog waveform data of the detected hitting sound are sampled at a time interval Δt and digitalized by discretizing a sound hitting waveform amplitude value. A data conversion means for converting into waveform data, and a percussion sound composed of the percussion time duration x, the percussion frequency y, and the percussion intensity z by performing time / frequency analysis on the converted digital waveform data. Time / frequency analysis means for calculating the analysis data (x, y, z) and the hit sound analysis data (x, y, z) in a three-dimensional coordinate space composed of the x-axis, y-axis, and z-axis orthogonal to each other. Display means for visually displaying the shape of the percussion surface obtained by plotting in a percussion analysis space;
B which is the sound hit duration x which is the barycentric position of the B zone curved surface which is the sound hitting curved surface in the second region from 345 Hz to 1.4 kHz where the value of the sound hitting frequency y is equal to or lower than the first frequency y1. evaluating means zone centroid time x _gb is is larger than the first determination time x _t1 selected from among 10msec to 15msec from slapping sound start evaluates that the internal defects present in the concrete member in the vicinity of the striking point concrete tapping sound inspection system, characterized in that it comprises and.   A sound detecting means for detecting a hitting sound generated when hitting the surface of a concrete member, and analog waveform data of the detected hitting sound are sampled at a time interval Δt and digitalized by discretizing a sound hitting waveform amplitude value. A data conversion means for converting into waveform data, and a percussion sound composed of the percussion time duration x, the percussion frequency y, and the percussion intensity z by performing time / frequency analysis on the converted digital waveform data. Time / frequency analysis means for calculating the analysis data (x, y, z) and the hit sound analysis data (x, y, z) in a three-dimensional coordinate space composed of the x-axis, y-axis, and z-axis orthogonal to each other. Display means for visually displaying the shape of the percussion surface obtained by plotting in a percussion analysis space;
C zone upper end time that is the sound hit duration x that is the upper end of the C zone curved surface that is the sounding curved surface in the third region centered at 86 Hz where the value of the sounding frequency y is equal to or lower than the second frequency y2. x _ec Is the second discrimination time x selected from 15 msec to 50 msec from the start of the hitting sound _t2 In the above case, the concrete sound-inspecting method comprising: an evaluation unit that evaluates that there is a portion having a poor support state behind the concrete member.

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